JP2012242175A - Light source color measuring apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source color measuring apparatus capable of performing accurate color measurement by a small-sized and easy design.SOLUTION: A light source color measuring apparatus 1 includes: a spectrometer 8 for spectrally diffracting a color of light from an LED 3; a transmission diffusion plate 4 for diffusing light from the LED 3; a polygonal light pipe 6 for equalizing intensity distribution of light guided to the spectrometer 8; and a bundle fiber 5 configured so that a plurality of fibers 5F are collected between the transmission diffusion plate 4 and the polygonal light pipe 6, one end of the bundle fiber 5 is opposed to the polygonal light pipe 6 and the other end is dispersed so as to be wider than the end face of the polygonal light pipe 6 and opposed to the transmission diffusion plate 4. Since angle dependence is eliminated and light with uniform intensity distribution can be inputted to the spectrometer 8, accurate color measurement can be achieved. Because of no use of an integrating sphere, color measurement can be performed by the small-sized and easily design.

Description

  The present invention relates to a light source color measuring apparatus that performs color measurement by splitting light from a light source.

  A light source color measuring device is used that measures the color of a light source using a spectrometer that splits the light emitted from the light source and measures the dispersed light. When an LED is used as the light source, the light emitted from the LED is received by the incident optical system, and the received light is guided to the spectrometer using an optical fiber. Then, the spectrum is measured by separating the light with a spectrometer. Thereby, the color measurement of LED is performed.

  An integrating sphere is mainly used as the incident optical system. As an example of the integrating sphere, there is a technique disclosed in Patent Document 1. The light emitted from the LED is highly angle dependent and the intensity distribution is non-uniform. The integrating sphere has an entrance port and an exit port, and guides light from the LED from the entrance port to the inside of the integrating sphere.

  The inside of the integrating sphere having a spherical shape is coated with a high reflectivity, and light from the incident port is multiple-reflected and emitted from the emission port. Thereby, when the light is spatially integrated inside the integrating sphere and the light is emitted from the emission port, the angle dependency is eliminated and the intensity distribution is uniform. An accurate color measurement of the LED can be performed by guiding the light to the spectrometer and performing the measurement.

  In some cases, a diffuser plate is used instead of an integrating sphere as the incident optical system. For example, the spectrometer of Patent Document 2 uses a diffusion plate. FIG. 6 shows a conventional incident optical system using a transmission type diffusing plate. The light emitted from the LED 101 enters the transmissive diffusion plate 102. The light from the LED 101 is diffused and transmitted by the transmission diffusion plate 102. Then, the transmitted light is incident on the light guide fiber 103. The light that has entered the light guide fiber 103 is input to the spectrometer, where it is dispersed to perform color measurement.

JP 2000-32129 A JP 2005-003389 A

  Since the integrating sphere eliminates the angle dependency and makes the intensity distribution uniform, accurate color measurement can be performed. However, the size of the integrating sphere becomes very large. For this reason, the size of the integrating sphere becomes excessively large with respect to a small light source such as an LED, and the integrating sphere becomes unsuitable for measuring a small light source. In addition, the integrating sphere is not easy to design because two members whose inner surfaces are processed to be hemispherical surfaces must be joined to make the interior completely spherical.

  On the other hand, the diffusion plate is suitable for a light source having a small size and is easy to design. However, light received within a predetermined range of the transmissive diffusion plate 102 is received by the end face of the small-diameter light guide fiber 103. That is, the light diffused in a wide area of the transmission diffusion plate 102 is received by the end face of the light guide fiber 103 having a narrow light receiving point. At this time, among the light rays that have been transmitted through the transmissive diffusion plate 102 and dispersed, light rays other than the center have an angle dependency. In particular, the angle dependence increases as the distance from the center increases.

  Also, the intensity distribution becomes non-uniform depending on the distance or positional relationship between the LED 101 and the transmissive diffusion plate 102. The entrance of the spectrometer is provided with a slit, and the light that has passed through this slit becomes the measurement target. At this time, if the light passing through the slit has an angle dependency and the intensity distribution is not uniform, accurate color measurement cannot be performed in the spectrometer.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a light source color measuring device that performs accurate color measurement with a small and easy design.

  In order to solve the above-described problems, a light source color measurement apparatus according to the present invention includes a spectrometer that spectrally measures the color of light from a light source, a light diffusing unit that diffuses light from the light source, and the spectrometer. Intensity equalizing means for equalizing the intensity distribution of the guided light, and a plurality of fibers are gathered between the light diffusing means and the intensity equalizing means so that one end faces the intensity equalizing means. And a fiber group in which the other end is dispersed so as to be wider than the end face of the strength uniformizing means and is opposed to the light diffusing means.

  According to this light source color measuring apparatus, the light diffusing means and the intensity uniformizing means are provided separately, and it is not necessary to use an integrating sphere, so that the apparatus can be miniaturized. The light diffused by the light diffusing means is received by the fiber group in which the fibers are dispersed, and collected and guided to the intensity uniformizing means, so that the angle dependence can be eliminated and the intensity distribution can be uniformized. Thereby, accurate color measurement can be realized.

  The light diffusing means is a transmissive or reflective diffusing plate, and the intensity equalizing means is a polygonal light pipe.

  A transmissive or reflective diffusion plate can be used as the light diffusing means, and a polygonal light pipe can be used as the intensity equalizing means. Since the dispersed fibers are gathered, the polygonal light pipe can be made thin and short.

  Moreover, when each fiber of the said fiber group is disperse | distributed, it is made to disperse | distribute so that each fiber may become a mutually equal space | interval.

  By equalizing the dispersion of each fiber of the fiber group, it is possible to perform uniform color measurement of light without uneven distribution.

  The polygonal light pipe is connected to the spectrometer.

  By connecting the polygonal light pipe to the spectrometer, means such as a light guide fiber can be omitted. Since a polygonal light pipe having a small diameter can be used, it can be directly connected to the spectrometer.

  In the present invention, the angle dependency is eliminated by diffusing the light from the light source with the light diffusing means and receiving it with the dispersed fiber. Then, by collecting the fibers and guiding them to the intensity equalizing means to equalize the intensity distribution, accurate color measurement can be performed. Since it can be realized without using an integrating sphere, it can be applied to color measurement of a small light source, and color measurement can be performed with an easy design.

It is a whole lineblock diagram of a light source color measuring device. It is a perspective view which shows the structure from a permeation | transmission diffusion plate to a light guide fiber. FIG. 4 is a side view of FIG. 3. It is sectional drawing of the front end side of a bundle fiber, and a base end side. It is a perspective view which shows the structure from a reflective diffuser plate to a light guide fiber. It is the conventional example which shows the state of light reception of a transmission diffusing plate.

  Embodiments of the present invention will be described below with reference to the drawings. The light source color measuring apparatus 1 according to the present embodiment includes a drive power source 2, an LED 3, a transmission diffusion plate 4, a bundle fiber 5, a polygonal light pipe 6, a light guide fiber 7, a spectrometer 8, and a computer 9. . The light source color measuring device 1 is a device that measures the color characteristics of the LED 3.

  The drive power source 2 is a power source that generates a predetermined current. The current generated by the drive power supply 2 is supplied to the LED 3. The LED 3 is a light source and emits light by a current supplied from the drive power supply 2. In addition, although LED3 is applied as a light source, you may apply arbitrary light sources, such as a lamp.

  The light emitted from the LED 3 enters the transmission diffusion plate 4. The transmissive diffusion plate 4 is a light diffusing unit, and diffuses and transmits the light emitted from the LED 3. The transmission diffusion plate 4 diffuses the incident light uniformly. The light from the LED 3 is incident on the transmission diffusion plate 4 at the surface, but all the light rays within the surface are uniformly dispersed. By guiding this dispersed light to the bundle fiber 5, the angle dependency of the light is eliminated.

  The bundle fiber 5 is a group of fibers in which a plurality of fibers 5F are bundled. One end (tip side 5A) of the bundle fiber 5 is arranged with the fibers 5F dispersed in order to receive light at multiple points. On the other hand, the other end (base end side 5B) has a configuration in which the fibers 5F are bundled together. Therefore, the bundle fiber 5 has a region in the direction orthogonal to the extending direction thereof changing between the distal end side 5A and the proximal end side 5B.

  The polygonal light pipe 6 is a strength equalizing means, and a glass rod of a polygonal column such as a quadrangular column or a hexagonal column can be used. The polygonal light pipe 6 faces the base end side 5B of the bundle fiber 5 and is arranged in contact with or non-contact with the bundle fiber 5. The light traveling through each fiber 5F of the bundle fiber 5 enters the polygonal light pipe 6. The polygonal light pipe 6 is subjected to multiple reflections within the surface, thereby making the light intensity distribution uniform.

  The light guide fiber 7 is connected to the polygonal light pipe 6 and inputs light having a uniform intensity distribution. The light guide fiber 7 is connected to the spectrometer 8, and light from the light guide fiber 7 enters the spectrometer 8. A slit is provided on the incident side of the spectrometer 8, and light passing through the slit is diffracted by the diffracting means and split. The spectrally separated light is detected by a detector and subjected to spectral measurement. The measured spectrum information is output to the computer 9. The calculator 9 performs a predetermined calculation based on the spectrum information and measures the color of the LED 3.

  Details of the configuration from the LED 3 to the light guide fiber 7 are shown in FIGS. The light emitted from the LED 3 spreads in a predetermined range and enters the transmission diffusion plate 4. Accordingly, light is incident on the transmission diffusion plate 4 at the surface. The light beam at the center of the surface is incident from the normal direction of the transmissive diffusion plate 4, but the light rays other than the center are incident on the transmissive diffusion plate 4 at a predetermined angle. In particular, the angle of the light beam in the end region of the surface is increased.

  The transmission diffusion plate 4 uniformly disperses each light ray incident on the surface. Thereby, the light rays at the center of the surface and the light rays other than the center are uniformly dispersed. That is, the light transmitted through the transmissive diffusion plate 4 is uniformly dispersed at any location. At this time, the fibers 5F are dispersedly arranged so that the uniformly dispersed light is received by the front end side 5A of the bundle fiber 5.

  As shown in FIG. 4 a), the cross section of the bundle fiber 5 at the distal end side 5 </ b> A has a plurality of fibers 5 </ b> F dispersed therein. That is, a predetermined gap is formed between adjacent fibers 5F. Thereby, the front end side 5A of the bundle fiber 5 forms a predetermined region 5C in a direction orthogonal to the extending direction of the fiber 5F.

  Accordingly, the light transmitted through the predetermined range of the transmission diffusion plate 4 is incident on each fiber 5F dispersedly arranged in the predetermined region 5C. That is, light that has passed through a predetermined range of the transmission diffusion plate 4 is incident on each fiber 5F in the predetermined region 5C. Light that is uniformly dispersed and transmitted from each part of the transmission diffusion plate 4 is incident on each fiber 5F. In FIG. 2, a light beam when attention is paid to one fiber 5F is indicated by a broken line. As shown by the broken line in the figure, one fiber 5F is incident with light uniformly dispersed at various angles. The same applies to the other fibers 5F, and uniformly dispersed light rays are incident in the same manner.

  For this reason, at the front end side 5A of the bundle fiber 5, uniformly dispersed light is input at multiple points (the same for each fiber 5F. In other words, there is no angle dependency in the light incident on each fiber 5F. Then, light having no angle dependency is guided through each fiber 5F.

  The fibers 5F are arranged so that the fibers 5F are dispersed on the distal end side 5A of the fibers 5F, but are arranged in a concentrated arrangement so that the fibers 5F are bundled on the proximal end side 5B. FIG. 4B) shows a cross section of the bundle fiber 5 at the proximal end side 5B. As shown in this figure, the fibers 5F are densely packed. Accordingly, the base end side 5B of the bundle fiber 5 forms a predetermined region 5D in a direction orthogonal to the extending direction of the fiber 5F.

  The region 5D is a region narrower than the region 5C. As a result, the fibers 5F that have been dispersedly arranged on the distal end side 5A of the bundle fiber 5 can be concentrated in a narrow region 5D. The region 5D is approximately the same size as the end face of the polygonal light pipe 6.

  The base end side 5 </ b> B of the bundle fiber 5 is opposed to the polygonal light pipe 6, and the light guided through each fiber 5 </ b> F of the bundle fiber 5 is incident on the polygonal light pipe 6. At this time, since the proximal end side 5B of the bundle fiber 5 is narrowed to the size of the region 5D, the polygonal light pipe 6 can also be thinned to substantially the same size.

  The polygonal light pipe 6 has a polygonal columnar shape, and incident light is subjected to multiple reflection inside, thereby uniforming the intensity distribution of the emitted light. In particular, the light incident on the polygonal light pipe 6 has an intensity distribution based on the positional relationship among the LED 3, the transmission diffusion plate 4, and the bundle fiber 5. This intensity distribution is made uniform by causing multiple reflections in the polygonal light pipe 6.

  Therefore, it is desirable to reduce the diameter of the polygonal light pipe 6 in order to cause multiple reflection inside. This is because when the polygonal light pipe 6 has a large diameter, in order to cause multiple reflection, the polygonal light pipe 6 must be lengthened correspondingly. Therefore, the polygonal light pipe 6 can be shortened by reducing the diameter thereof, and the polygonal light pipe 6 can be greatly reduced in size.

  Light emitted from the polygonal light pipe 6 enters the light guide fiber 7. The light emitted from the polygonal light pipe 6 has a uniform intensity distribution, and since the light transmitted through the transmission diffusion plate 4 is received by the bundle fiber 5 in a distributed arrangement, the angle dependency is eliminated. . Therefore, light having no angle dependency and uniform intensity distribution is incident on the light guide fiber 7, and this light is input to the spectrometer 8 by the light guide fiber 7.

  Therefore, the spectrometer 8 receives light having no angle dependency and a uniform intensity distribution. The spectrometer 8 diffracts the light received by the diffracting means and performs spectrum measurement. At this time, accurate color measurement can be performed by performing spectrum measurement of light having no angle dependency and uniform intensity distribution.

  As described above, in the present embodiment, the light from the LED 3 is uniformly diffused in the transmission diffusion plate 4 and is incident on the bundle fiber 5 in which the fibers 5F are dispersedly arranged. Since the uniformly dispersed light is uniformly incident on each fiber 5F on the distal end side 5A, the angle dependency is eliminated. Then, the light is incident on the polygonal light pipe 6 through the bundle fiber 5 and is reflected by the polygonal light pipe 6 to make the intensity distribution uniform. Thereby, since the light with a uniform intensity distribution without angle dependency is detected in the spectrometer 8, accurate color measurement can be performed.

  The bundle fiber 5 is dispersed on the distal end side 5A facing the transmission diffusion plate 4 and bundled and gathered on the proximal end side 5B facing the polygonal light pipe 6. As a result, a wide range of light uniformly dispersed from the transmissive diffusion plate 4 can be captured and guided to the polygonal light pipe 6.

  In addition, since the sizes of the region 5C on the distal end side 5A and the region 5D on the proximal end side 5B of the bundle fiber 5 are changed, the light captured in a wide range on the distal end side 5A can be collected on the proximal end side 5B. it can. Thereby, the polygonal light pipe 6 can be made into a small diameter, and the size of the polygonal light pipe 6 can be significantly reduced. As a result, the overall size of the light source color measuring device 1 is also compact.

  In the above description, the transmission diffusion plate 4 is used as the light diffusion means, but a reflection diffusion plate 10 may be used as shown in FIG. When the light emitted from the LED 3 is reflected by the reflection diffusion plate 10, the light is reflected so as to diffuse. Thereby, the same effect as when the transmission diffusion plate 4 is used can be obtained.

  In addition, the polygonal light pipe 6 is used to obtain the effect of uniforming the intensity distribution. However, when the light guide fiber 7 can be provided with the uniform effect of the intensity distribution, the polygonal light pipe 6 is used. May be omitted. In this case, the light guiding fiber 7 serves as the strength uniformizing means. If the polygonal light pipe 6 can be directly connected to the spectrometer 8, the light guide fiber 7 may be omitted. Thereby, the light guide fiber 7 can be omitted and the apparatus configuration can be simplified.

1 Light source color measuring device 3 LED
4 Transmission diffusion plate 5 Bundle fiber 5A Tip side 5B Base end side 5F Fiber 6 Polygonal light pipe 7 Light guide fiber 8 Spectrometer 9 Computer 10 Reflection diffusion plate

Claims (4)

A spectrometer for spectroscopically measuring the color of light from the light source;
A light diffusing means for diffusing light from the light source;
Intensity uniformizing means for uniformizing the intensity distribution of the light guided to the spectrometer;
A plurality of fibers are gathered between the light diffusing means and the intensity equalizing means so that one end faces the intensity equalizing means and the other end is dispersed so as to be wider than the end face of the intensity equalizing means. And a group of fibers opposed to the light diffusing means,
A light source color measuring device comprising: The light source color measuring apparatus according to claim 1, wherein the light diffusing means is a transmissive or reflective diffusing plate, and the intensity equalizing means is a polygonal light pipe. The light source color measuring device according to claim 2, wherein when the fibers of the fiber group are dispersed, the fibers are dispersed so that the fibers are evenly spaced from each other. The light source color measuring device according to claim 3, wherein the polygonal light pipe is connected to the spectrometer.

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